The death of footballer Phil O'Donnell has again highlighted the tragedy of apparently fit and healthy individuals dying with shocking speed.

It is believed Mr O'Donnell, 35, suffered some form of seizure towards the end of Motherwell's Scottish Premier League game.

Whatever the tragic circumstances behind Mr O'Donnell's death, it is the sudden nature of his collapse that has only added to the shock for his family and football fans alike.

Other sudden deaths include 15-year-old Daniel Yorath, son of the former Wales football manager Terry Yorath, who died in his father's arms from a heart condition known as hypertrophic cardiomyopathy.

Cameroon midfielder Marc-Vivien Foe, 28, died in 2003 after collapsing during an international match in France from hypertrophic cardiomyopathy, and in August Spanish international defender Antonio Puerta, 22, died after suffering a heart attack while playing for his club side Sevilla.

When I started CRY I was told I was wasting my time and that it was so rare it wasn't worth doing anything about

Alison Cox

Sudden Arrhythmic Death Syndrome (SADS) is an umbrella term for heart conditions that lead to sudden death.

Alison Cox started Cardiac Risk in the Young (CRY) in 1995 and has expressed her sympathy for Mr O'Donnell's family, including his wife and four children.

Time will tell as to the exact nature of the footballer's early death, but in the meantime Mrs Cox says cases of SADS can affect people from all backgrounds, regardless of whether or not they engaged in sport.

"CRY advocates a screening programme. In fact, we screen in clubs, schools and in the community.

"We would like to see screening introduced for all children before they leave school," she explains.

"We're developing a network of screening clinics throughout the country, so we do believe that it's very advisable to screen whether you play sport or not, because although the deaths you hear about are deaths in sport, they're just as common in the community.

"When I started CRY I was told I was wasting my time and that it was so rare it wasn't worth doing anything about - there was only one death a week.

"We now know there's at least eight and there could be as many as 16 deaths a week. There's a great deal more going on than people recognise."

Tennis support

After her son Steve, now 33, was diagnosed with a heart abnormality at the age of 18, further tests showed that Mrs Cox also carried the same abnormality.

She was spurred on to launch CRY, initially raising £10,000 through a skipathon towards a £120,000 machine to take echocardiograms. It was purchased two years later.

With the support of tennis player Jeremy Bates, CRY set up the first cardiac screening programme in sport in the UK by testing elite tennis players. One of the first to be screened in an early pilot scheme was the then 18-year-old Tim Henman.

Tim Henman was screened for SADS as an 18-year-old

Mrs Cox said the impact of a SADS death on a family is "absolutely catastrophic".

She added: "Not only have they got to deal with the death of a loved one, but a mother or father has to deal with the fact that 50% of SADS conditions are genetic, which means their children could possibly have the same condition also.

"And the problem is that often the first presentation of the problem is sudden death.

"In Italy they have been screening in sport for 22 years and have more or less eliminated SADS from sport now."

CRY's campaigning led to the Department of Health announcing the launch of the new National Service Framework chapter on Arrhythmias and Sudden Cardiac Death in 2004.

This sets out new measures to improve treatment for cardiac arrhythmias - irregular heartbeats - and measures to tackle the problem of SADS.

Mrs Cox was also awarded an MBE in June, but is quick to point out that she does not see that award as a personal accolade.

"The MBE is on behalf of all our bereaved families, and a tribute to how hard they have worked to raise awareness about SADS."